Many computer systems use dynamic random access memory (DRAM) as system memory to temporarily store an operating system, critical applications, and data. With widespread use of multi-core processors, particularly, in servers and workstations, higher capacity and faster memory devices are needed to catch up with the computing power of these processors, thereby reducing the processor-memory performance gap and allowing the applications to use the full processing speed of modern processors.
One way to narrow the processor-memory performance gap is to develop innovative technologies to enhance characteristics of DRAM chips in terms of capacity and bandwidth. Yet another way is to increase storage capacity by stacking memory chips, while using existing DRAM technologies. For example, in servers and storage applications, chip stacking can be used to obtain high memory densities in a smaller space and most likely at a lower cost. Other industrial or embedded applications may demand different memory requirements, but typically high-density chip stacking is needed where space is constrained, therefore requiring more memory capacity on the same or a smaller memory module form factor.
One way to form stacked memory chips involves mounting two or more memory chips, one on top of the other, and interconnecting them using through-silicon-vias (TSVs).